When running the code below, I get an error about trying to index into an environment. I think that a safety check is needed in the p$callable() function, but I'm not sure what.
library(rly)
TOKENS <- c("MONTH", "WEEK", "DAY", "HOUR", "MINUTE", "SECOND",
"INTEGER", "PREPOST")
LITERALS <- c(".", "-")
Lexer <- R6::R6Class(
"Lexer",
public=list(
tokens=TOKENS,
literals=LITERALS,
t_MONTH="(?:mon(?:th)?|MON(?:TH)?)",
t_WEEK="(?:W(?:EE)?K|w(?:ee)?k)",
t_DAY="(?:D(?:A)?Y|d(?:a)?y)",
t_HOUR="(?:H(?:(?:OU)?R)?|h(?:(?:ou)?r)?)",
t_MINUTE="(?:M(?:IN(?:UTE)?)?|m(?:in(?:ute)?)?)",
t_SECOND="(?:S(?:EC(?:OND)?)?|s(?:ec(?:ond)?)?)",
t_INTEGER="[0-9]+",
t_ignore=" \t",
t_error=function(t) {
cat(sprintf("Illegal character '%s'", t$value[1]))
t$lexer$skip(1)
return(t)
}
)
)
Parser <- R6::R6Class(
"Parser",
public = list(
tokens = TOKENS,
literals = LITERALS,
# Parsing rules
precedence = list(),
# dictionary of names
names = new.env(hash=TRUE),
p_valueunit_prepost=function(doc="valueunit : valueunit PREPOST", p) {
p$set(1, self$names[[as.character(p$get(2))]])
},
p_valueunit_base=function(doc="valueunit : value timeunit
| timeunit value", p) {
p$set(1, self$names[[as.character(p$get(2))]])
},
p_value_negative=function(doc="value : '-' value", p) {
p$set(1, self$names[[as.character(p$get(2))]])
},
p_value_float=function(doc="value : INTEGER '.' INTEGER", p) {
p$set(1, self$names[[as.character(p$get(2))]])
},
p_value_integer=function(doc="value : INTEGER", p) {
p$set(1, self$names[[as.character(p$get(2))]])
},
p_time_unit=function(doc="timeunit : MONTH
| WEEK
| DAY
| HOUR
| MINUTE
| SECOND", p) {
p$set(1, self$names[[as.character(p$get(2))]])
},
p_error = function(p) {
if(is.null(p)) cat("Syntax error at EOF")
else cat(sprintf("Syntax error at '%s'", p$value))
}
)
)
lexer <- rly::lex(Lexer)
parser <- rly::yacc(Parser)
parser$parse("15min", lexer)
#> Error in value[[3L]](cond): wrong arguments for subsetting an environmentCreated on 2018-12-08 by the reprex package (v0.2.0).
When running the code below, I get an error about trying to index into an environment. I think that a safety check is needed in the
p$callable()function, but I'm not sure what.Created on 2018-12-08 by the reprex package (v0.2.0).